Phased Array Noise Source Localization Measurements of an F404 Nozzle Plume at Both Full and Model Scale PDF Download

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781719383073
Category :
Languages : en
Pages : 34

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Book Description
A 48-microphone planar phased array system was used to acquire jet noise source localization data on both a full-scale F404-GE-F400 engine and on a 1/4th scale model of a F400 series nozzle. The full-scale engine test data show the location of the dominant noise sources in the jet plume as a function of frequency for the engine in both baseline (no chevron) and chevron configurations. Data are presented for the engine operating both with and without afterburners. Based on lessons learned during this test, a set of recommendations are provided regarding how the phased array measurement system could be modified in order to obtain more useful acoustic source localization data on high-performance military engines in the future. The data obtained on the 1/4th scale F400 series nozzle provide useful insights regarding the full-scale engine jet noise source mechanisms, and document some of the differences associated with testing at model-scale versus fullscale. Podboy, Gary G. and Bridges, James E. and Henderson, Brenda S. Glenn Research Center JET AIRCRAFT NOISE; NOISE GENERATORS; SOUND GENERATORS; ENGINE NOISE; ENGINE TESTS; FULL SCALE TESTS; PHASED ARRAYS; PLUMES; PLANAR STRUCTURES; SCALE MODELS

Author: Thomas J. Mueller
Publisher: Springer Science & Business Media
ISBN: 3662050587
Category : Technology & Engineering
Languages : en
Pages : 327

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The book describes recent developments in aeroacoustic measurements in wind tunnels and the interpretation of the resulting data. The reader will find the latest measurement techniques described along with examples of the results.

Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1218

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Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721648238
Category :
Languages : en
Pages : 34

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The aim of this investigation was to use the linear phased array (LPA) microphones and infrared (IR) imaging to study the effects of advanced nozzle-mixing techniques on jet noise reduction. Several full-scale engine nozzles were tested at varying power cycles with the linear phased array setup parallel to the jet axis. The array consisted of 16 sparsely distributed microphones. The phased array microphone measurements were taken at a distance of 51.0 ft (15.5 m) from the jet axis, and the results were used to obtain relative overall sound pressure levels from one nozzle design to the other. The IR imaging system was used to acquire real-time dynamic thermal patterns of the exhaust jet from the nozzles tested. The IR camera measured the IR radiation from the nozzle exit to a distance of six fan diameters (X/D(sub FAN) = 6), along the jet plume axis. The images confirmed the expected jet plume mixing intensity, and the phased array results showed the differences in sound pressure level with respect to nozzle configurations. The results show the effects of changes in configurations to the exit nozzles on both the flows mixing patterns and radiant energy dissipation patterns. By comparing the results from these two measurements, a relationship between noise reduction and core/bypass flow mixing is demonstrated. Agboola, Femi A. and Bridges, James and Saiyed, Naseem Glenn Research Center NASA/TM-2004-213042, E-14479

Author: S. Mukherjee
Publisher: Geological Society of London
ISBN: 1862397031
Category : Science
Languages : en
Pages : 325

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The Himalayan mountain belt, which developed during the India–Asia collision starting about 55 Ma ago, is a dramatically active orogen and it is regarded as the classic collisional orogen. It is characterized by an impressively continuous 2500 km of tectonic units, thrusts and normal faults, as well as large volumes of high-grade metamorphic rocks and granites exposed at the surface. This constitutes an invaluable field laboratory, where amazing crustal sections can be observed directly in very deep gorges. It is possible to unravel the tectonic and metamorphic evolution of litho-units, to observe the mechanisms of exhumation of deep-seated rocks and the propagation of the deformation. Himalayan tectonics has been the target of many studies from numerous international researchers over the years. In the last 15 years there has been an explosion of data and theories from both geological and geophysical perspectives. This book presents the results of integrated multidisciplinary studies, including geology, petrology, magmatism, geochemistry, geochronology and geophysics, of the structures and processes affecting the continental lithosphere. These processes and their spatial and temporal evolution have major consequences on the geometry and kinematics of the India–Eurasia collision zone.

Author:
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 4

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Author: Dmitri Kuzmin
Publisher: Springer Science & Business Media
ISBN: 9400740379
Category : Science
Languages : en
Pages : 462

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Addressing students and researchers as well as Computational Fluid Dynamics practitioners, this book is the most comprehensive review of high-resolution schemes based on the principle of Flux-Corrected Transport (FCT). The foreword by J.P. Boris and historical note by D.L. Book describe the development of the classical FCT methodology for convection-dominated transport problems, while the design philosophy behind modern FCT schemes is explained by S.T. Zalesak. The subsequent chapters present various improvements and generalizations proposed over the past three decades. In this new edition, recent results are integrated into existing chapters in order to describe significant advances since the publication of the first edition. Also, 3 new chapters were added in order to cover the following topics: algebraic flux correction for finite elements, iterative and linearized FCT schemes, TVD-like flux limiters, acceleration of explicit and implicit solvers, mesh adaptation, failsafe limiting for systems of conservation laws, flux-corrected interpolation (remapping), positivity preservation in RANS turbulence models, and the use of FCT as an implicit subgrid scale model for large eddy simulations.

Author: Ellis D. Avner
Publisher: Springer Science & Business Media
ISBN: 3540763279
Category : Medical
Languages : en
Pages : 2059

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Book Description
Here is an extensive update of Pediatric Nephrology, which has become the standard reference text in the field. It is global in perspective and reflects the international group of editors, who are well-recognized experts in pediatric nephrology. Within this text, the development of kidney structure and function is followed by detailed and comprehensive chapters on all childhood kidney diseases.

Author: Holger Babinsky
Publisher: Cambridge University Press
ISBN: 1139498649
Category : Technology & Engineering
Languages : en
Pages : 481

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Book Description
Shock wave-boundary-layer interaction (SBLI) is a fundamental phenomenon in gas dynamics that is observed in many practical situations, ranging from transonic aircraft wings to hypersonic vehicles and engines. SBLIs have the potential to pose serious problems in a flowfield; hence they often prove to be a critical - or even design limiting - issue for many aerospace applications. This is the first book devoted solely to a comprehensive, state-of-the-art explanation of this phenomenon. It includes a description of the basic fluid mechanics of SBLIs plus contributions from leading international experts who share their insight into their physics and the impact they have in practical flow situations. This book is for practitioners and graduate students in aerodynamics who wish to familiarize themselves with all aspects of SBLI flows. It is a valuable resource for specialists because it compiles experimental, computational and theoretical knowledge in one place.

Author: Stockholm International Peace Research Institute
Publisher: Oxford University Press, USA
ISBN: 9780198291824
Category : History
Languages : en
Pages : 0

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Book Description
The SIPRI Yearbook 1994 continues SIPRI's review of the latest developments in nuclear weapons, world military expenditure, the international arms trade and arms production, chemical and biological weapons, the proliferation of ballistic missile technology, armed conflicts in 1993, and nuclear and conventional arms control. It is the most complete and authoritative source available for up-to-date information in war studies, strategic studies, peace studies, and international relations.